After the electrode coating and drying, the peeling strength between the active material and the current collector foil is very low, and it needs to be rolled to enhance the bonding strength of the active material and the foil, to prevent peeling during immersion in electrolyte and battery use. At the same time, the roller pressing of the electrode can compress the volume of the cell, improve the energy density of the cell, reduce the porosity between the active material, the conductive agent and the binder inside the electrode, reduce the resistance of the battery, and improve the performance of the battery!

The compaction density of the electrode has an important influence on the electrochemical performance of the battery. Within a certain range, as the compaction density increases, the distance between the active material particles decreases, the contact area increases, and the number of paths and bridges conducive to ion conduction increase, in the macroscopic aspect, the internal resistance of the battery is reduced. However, if the compaction density of the electrode is too high, the contact between the active material particles is too close, and the electronic conductivity increases. However, the reduction or blockage of lithium ion channels is not conducive to the development of capacity. When discharging, the polarization increases, the voltage decreases, and the capacity decreases. When the compaction density is too small, the particle spacing is large, the lithium ion movement channel is smooth, and the electrolyte absorption capacity is strong, which is conducive to the movement of lithium ions inside the battery, but because the contact between particles is not close enough, it is not conducive to the conduction of electrons, and it is easy to lead to an increase in polarization during discharge.

The purpose of rolling is as follows:

1) Ensure that the surface of the electrode is smooth and flat, and prevent the burr on the coating surface from piercing the diaphragm and causing a short circuit;

2) Compact the coating material of the electrode to reduce the volume of the electrode to improve the energy density of the battery;

3) Make the contact between the active material and the conductive agent particles more closely, and improve the electronic conductivity;

4) Enhance the bonding strength of the coating material and the current collector, reduce the occurrence of powder drop of the battery electrode during the cycle, and improve the cycle life and safety performance of the battery.

TOB New Energy can provide battery electrode rolling press machine and provide customized services according to your requirements.

TOB NEW ENERGY LIMTED provides "one-stop" solution and a "Turn key" project for you, also provide a technology improvement program, if you are interested in it, please feel free to contact us, looking forward to discuss with you.

Thank you for reading!

Contact person:Gavin Zhu (Engineer & Sales)

Email:tob.gavin@tobmachine.com

Skype: tob.gavin@tobmachine.com

Wechat: TOB-007